The proposed work during the 1979-1980 period will consist of 3 parts: 1. Longitudinal study; a. The completion of data collection of a 6-year longitudinal follow-up of experiments with 250 subjects ranging in age from 35-75 years. 2. Cross Sectional Experiments; Four cross sectional experiments will be conducted to examine age related differences in selected information processing abilities. a. The effect of information feedback on the alerting functions (measured by reaction latency) of young and elderly adults, b. The effect of semantic facilitation in verbal processing, c. Age related differences in mental rotation processing rate, d. Individual difference in simple reaction time parameters and the predictive power of these parameters on learning functions. 3. Imagery Study; One study will be conducted to further examine the age-related qualitative difference in imagery mnemonics.